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POF Applications
Published in Marcelo Martins Werneck, Regina Célia da Silva Barros Allil, Plastic Optical Fiber Sensors, 2019
Disconnectors are mechanical maneuvering devices which, in the open position, ensure an insulation distance and, in the closed position, maintain the continuity of the electric circuit under specified conditions. The disconnector can only be operated either to open or to close when a negligible current is passing through it and when there are no significant or sudden variations of voltage between its terminals. It is also capable of conducting currents under normal circuit conditions and, for specified times, currents under abnormal conditions, such as short circuit currents. Figure 15.1 shows a 720-kV disconnector opening with an electric arc following its contact blades.
Power Distribution System, Unsymmetrical Failures, and Power System Protections
Published in Pedro Ponce, Arturo Molina, Omar Mata, Luis Ibarra, Brian MacCleery, Power System Fundamentals, 2017
Pedro Ponce, Arturo Molina, Omar Mata, Luis Ibarra, Brian MacCleery
In Figure 7.1, the basic structure of a power distribution system is shown. This is the simplest structure where the load is unidirectional from the generators to the loads. The most basic elements of a distribution scheme are also presented: electric generators, transformers, circuit breakers, and disconnector switches. The principal difference between circuit breakers and disconnectors is that the former are used to protect the circuit from overloads and short circuit conditions, while the disconnection switches are employed when a circuit is required to be disconnected from the power supply. This element does not have any protection at high voltages and it requires a circuit breaker before the switch blades are opened.
Hardware for Distribution Systems
Published in James Northcote-Green, Robert Wilson, Control and Automation of Electrical Power Distribution Systems, 2017
James Northcote-Green, Robert Wilson
A disconnector is defined as a mechanical switching device that provides in the open position a specified isolating distance. It should be capable of opening and closing a circuit when negligible current is broken or made. It should be noted that disconnectors are unreliable for breaking capacitive current, with capacitive currents of less than 1 A causing damage to some types of disconnector. Although it should be capable of carrying normal load current and also carrying for a specified time currents under abnormal conditions such as for a short circuit, a disconnector is not capable of making or breaking short-circuit currents.
Quantifying the seismic risk for electric power distribution systems
Published in Structure and Infrastructure Engineering, 2021
Yang Liu, Liam Wotherspoon, Nirmal-Kumar C. Nair, Daniel Blake
Note that due to the ‘N-1’ security requirement, the two transformers are designed to be 50% loaded under normal operation condition so that even a single transformer has sufficient capacity to support the entire network under emergency or maintenance conditions on the other. Therefore, the availability of a single transformer as well as the associated switch gears is required to ensure the availability of outgoing feeders. The logic described above can be expressed as the following Boolean expressions, where denotes availability of the outgoing feeder. denotes the functional status of the disconnector, circuit breaker, transformer and bus bar, respectively:
Workers’ exposure to electric fields during the task ‘maintenance of an operating device of circuit breaker from a service platform’ at 110-kV substations
Published in International Journal of Occupational Safety and Ergonomics, 2019
Leena Korpinen, Rauno Pääkkönen
In earlier studies [5,6], the exposure to electric fields at service platforms at 400-kV substations was investigated. For example, workers performed maintenance of an operating device of a disconnector and of a circuit breaker from a service platform at 400-kV substations. The maximum electric field of tasks at service platforms was 36.5 kV⋅m−1 [5]. In earlier measurements at 110-kV substations in the Tampere region, the highest electric field was 15.5 kV⋅m−1 when working at a service platform [7]. In the large measurement project of EMF exposure at 110-kV substations, we measured the electric and magnetic fields during various work tasks at 16 substations [8]. The maximum value of electric fields was 15.5 kV⋅m−1 for the task ‘maintenance of an operating device of circuit breaker from a service platform’. The currents associated with 110-kV substation tasks were also published earlier [9].
Reduction of the DC Circuit Breaker Requirements by Bidirectional Solid-State Fault Current Limiter in DC Grid
Published in Electric Power Components and Systems, 2023
Ali Kian, Masoud Radmehr, Amangaldi Koochaki
To model the DCCB, the hybrid DC circuit breaker (HDCB), which is reported in Ref. [24] is used. Figures 7(a) and 7(b) demonstrate the schematic diagram of HDCB and the sequence operating mechanism of the HDCB, respectively. Considering Figure 7(a), it is composed of the following parts: RDB: residual DC current breaker,UFD: ultra-fast disconnector,LCS: load commutation-switch,MDB: main DC breaker.